Found this info on the web;
"There are actually two versions of the drive. The initial release uses the familiar AHCI protocol, while a newer variant adheres to the NVM Express standard. The AHCI model is compatible with a broader range of motherboards and available from a wider selection of vendors."
The NVMe version is also suppose to be quicker but in reality there isn't much difference;
I think you would need a motherboard with a M.2 NVMe socket to see any real difference in speed compared to the older AHCI version.
I understand it is only the newer HP Zx40 series range that supports NVMe drives but not 100% certain. It would definitely be a challenge trying to get one to work in a HZ Zx20 series.
My SM951 in CrystalDiskMark 5;
